Commonly known in the art are heat exchangers used in connection with an automotive vehicle for cooling the engine thereof. The heat exchanger generally comprises an upper and lower manifold for providing fluid reservoirs and a plurality of cooling tubes extending between the manifolds to provide fluid communication therebetween. Coolant passes through the upper and lower manifolds. These types of heat exchangers are liquid to air because liquid passes through the tanks and tubes while air is passed externally in between the tubes for cooling the fluid therein. There are also air to air heat exchangers wherein air is passed within the tubes and air is passed externally thereover for heat exchange.
Heat exchangers also include fin structures disposed between coolant tubes for directing ambient air about the coolant tubes. Such fins enhance heat exchanger performance and are common in the art as shown in U.S. Pat. No. 4,821,795 to Lu, assigned to the assignee of the subject invention.
It has been important to maximize heat transfer between the fin and the fluid tube by turbulating the passing air over the fins to maximize the amount of cold air contacting the surface area of the fins. Also, a concern is to minimize the pressure drop in air passing through the exchanger. One type of heat exchanger utilizing various configurations of fins is disclosed in U.S. Pat. No. 3,298,432, issued Jan. 17, 1967 in the name of Prezyborowski. This patent discloses a heat exchanger including a plurality of spaced fluid tubes with fins disposed in a corrugated manner therebetween. As best shown in FIG. 7, the fins include a plurality of sinusoidal wall sections at the ends thereof. In addition, several wall sections along a middle portion of each fin include louvers thereon. The sinusoidal wall sections may also be included within the center of the length of fins.
A problem with these types of prior systems is the significant pressure drop across the louvered fins.